Ceramic having a functional coating

Abstract

The present invention relates to material composites composed of a ceramic substrate having a functional coating and to the production and use of said material composites.

1 .- 18 . (canceled) 
     
     
         19 . A material composite comprising a ceramic substrate having a functional coating, which functional coating comprises at least one functional layer. 
     
     
         20 . The material composite according to  claim 19 , wherein the ceramic substrate comprises a polycrystalline ceramic or a monocrystal. 
     
     
         21 . The material composite according to  claim 20 , wherein the polycrystalline ceramic is at least 99 vol % crystalline. 
     
     
         22 . The material composite according to  claim 19 , wherein the ceramic substrate or the functional coating or the material composite is transparent. 
     
     
         23 . The material composite according to  claim 19 , wherein the functional coating makes the material composite more mechanically, thermally, and/or chemically resistant. 
     
     
         24 . The material composite according to  claim 19 , wherein the at least one functional layer selects the transmission of electromagnetic waves in an absorbing, reflecting, or scattering manner, i.e., restricts said transmission in dependence on wavelength, particularly in the visible range. 
     
     
         25 . The material composite according to  claim 19 , wherein the material composite has at least one colorless functional layer and/or a colorless ceramic substrate. 
     
     
         26 . The material composite according to  claim 19 , wherein the at least one functional layer of the functional coating has a thickness of less than 100 μm, preferably less than 1 μm, and highly especially preferably less than 0.15 μm, and has a fluctuation range of the real in-line transmission of less than 10% in a wavelength range of 420 to 650 nm. 
     
     
         27 . The material composite according to  claim 19 , wherein the at least one functional layer has a reflection-reducing effect, so that the material composite composed of the ceramic substrate and the functional layer has a higher RIT than the ceramic substrate without the functional layer, according to the following relationship:
   RIT max =1 −R   max          R   max =1−2×(( n   surroundings   −n   substrate )/( n   substrate   +n   surroundings ))
   R max =maximum reflection   n surroundings =index of refraction of the surrounding medium   n substrate =index of refraction of the material composite   
     
     
         28 . The material composite according to  claim 19 , wherein the at least one functional layer has a reflection-increasing effect, so that the material composite composed of the ceramic substrate and the functional layer has higher reflection than the ceramic substrate without the functional layer, according to the following relationship:
     R   max =1−2×( n   surroundings   −n   substrate )/( n   substrate   +n   surroundings ))
   R max =maximum reflection   n surroundings =index of refraction of the surrounding medium   n substrate =index of refraction of the material composite   
     
     
         29 . The material composite according to  claim 19 , wherein the functional coating comprises or consists of several functional layers. 
     
     
         30 . The material composite according to  claim 19 , wherein the functional coating has, as an outermost layer in contact with the surroundings, a layer having an index of refraction n of 1.38 to 1.55. 
     
     
         31 . The material composite according to  claim 19 , wherein the functional coating has, as an outermost layer in contact with the surroundings, a layer that levels out surface damage and thereby increases the strength of the material composite and/or narrows down the limit values of the strengths and/or reduces the standard deviation. 
     
     
         32 . The material composite according to  claim 19 , wherein the functional coating was produced with an energy input between 55 and 135 kJ into the functional layer, whereby the layer adhesion in the scratch test is increased by at least 10 mN. 
     
     
         33 . The material composite according to  claim 19 , wherein the functional coating was produced with an energy input between 55 and 135 kJ into the functional layer, whereby the average layer hardness H IT  (O&P) in the nanoindentation test is increased by at least 100 MPa. 
     
     
         34 . The material composite according to  claim 19 , wherein the functional coating was produced with an energy input between 55 and 135 kJ into the functional layer, whereby the average resistance to Hertzian stress is increased by at least 5 N/m 2 . 
     
     
         35 . The material composite according to  claim 23 , wherein the functional coating comprises or consists of several functional layers. 
     
     
         36 . A method for producing a material composite composed of a ceramic substrate having a functional coating, which functional coating comprises at least one functional layer, comprising depositing the at least one functional layer is deposited on the ceramic substrate by a method selected from the group consisting of physical vapor deposition, sol-gel, spin-on-disk, plasma assisted chemical vapor deposition and chemical vapor deposition. 
     
     
         37 . The method according to  claim 35 , wherein the at least one functional layer is applied by means of a sol-gel method and at least said functional layer is baked at a temperature between 300 and 1200° C.